Nutritionist doctor man

The prevalence of nonalcoholic fatty liver disease (NAFLD) has skyrocketed over the past recent years. NAFLD encompasses the spectrum of liver diseases from steatosis alone (mild hepatic fat accumulation), steatosis with mild lobular inflammation to non-alcoholic steatohepatitis. The most severe cases of NAFLD are characterized liver fibrosis and cirrhosis. In the United States, approximately 30% of the population has NAFLD and there are good reasons to believe that similar numbers could soon be observed in Europe if this trend continues. There is also clear evidence suggesting that NAFLD is a direct consequence of the Western lifestyle and that obesity and type 2 diabetes are closely associated with NAFLD presence and progression. The identification of patients with NAFLD in the clinic is a challenge and although some studies have tested the impact of clinical interventions on NAFLD, the scientific literature on the management of patients across the spectrum of NAFLD is scarce.

A recent article published in the Journal of the American Medical Association presents a systematic review of the literature on NAFLD that was performed by Dr. Mary E. Rinella from Northwestern University in Chicago (http://jama.jamanetwork.com/article.aspx?articleid=2319168). The objective of the systematic review was to collide all the available literature on NAFLD to determine the causes of NAFLD, its prevalence, how we should assess it and how we should treat it. It came as no surprise that abdominal obesity, hypertension, dyslipidemia, type 2 diabetes and metabolic syndrome were identified as the established risk factors for NAFLD. Indeed, visceral or intra-abdominal adipose tissue accumulation, low-grade inflammation and insulin resistance are three major biological determinants of NAFLD. Additionally, visceral adiposity and many of the above risk factors for NAFLD are attributable to a significant extent to our sedentary lifestyle. Unfortunately, the specific association between lifestyle-related risk factors such as physical activity, sedentary time as well as diet quality and quantity, sugar consumption, etc. were not factored in the literature review. Indeed, several other studies have linked these lifestyle behaviours to hepatic fat accumulation and NAFLD.  On the other hand, discussing on the potential treatment strategies for NAFLD, Dr. Rinella did refer to many studies on lifestyle-based intervention that were performed in the context of NAFLD. For instance, it has been shown that loss of 10% of body weight was associated with improvement in NAFLD at the histological level. Additionally, in a study including 154 participants, resolution of NAFLD was observed in 64% of participants referred to a lifestyle intervention that included nutritional advice offered by a registered dietitian and participation on moderate intensity exercise three times per week. In another study, the adoption of a Mediterranean dietary pattern was shown to provide significant improvement in NAFLD, even in the absence of weight loss. Although there is clear evidence suggesting that physical activity and exercise reduce hepatic fat accumulation (again with or without weight loss), there is little information on the most optimal type of exercise that one needs to perform to optimally manage NAFLD.

The author also identified some drugs that could be helpful for the managements of NAFLD such as vitamin E, pioglitazone and pentoxifylline. However, few of them have been proven effective for the management of NAFLD and even fewer of them are actually approved in US and Europe. Finally, an interesting and innovative multi-marker approach was proposed to identify patients with NAFLD in clinical practice. Whether this would improve risk stratification needs to be determined. This could however help health professionals identify patients that would benefit the most from therapeutic interventions. For that matter, the systematic review clearly points to lifestyle-based interventions aiming at improving physical activity levels and improving nutritional quality as our best chance of preventing and combatting this emerging disease.